Electric switch



0a. 1, 1930. E. Mom; 1.111.881

ELECTRIC SWITCH Filed April 12, 1926 2 Sheets-Shoot 1 IN VEN TOR. IRA E.MCABE.

BYM M ATTORNEYS.

Oct. 7,1930. I. E. M cABE ELECTRIC SWITCH Filed April 12 1926 IINVENTOR.

IRA c. was: 2 BY 0p A TTORNEYS.

Patented Oct. 7, 1930 PATENT OFFICE IRA. E. MCC ABE, 01' CHICAGO,ILLINOIS ELECTRIC SWITCH Application filed April 12,

This invention relates to improvements in electric switches and moreparticularly to-a switch of the mercury tube type of such constructionas to be actuated to make or break 5 the circuit by the action ofradiant energy.

A switch of this type and constructed in accordance with this inventionmay be used to great advantage when employed to be actuatedby radiantenergy from an actinic source in all kinds of signal equipment where itis desired to control an electric circuit to produce a light betweensun-setand sunrise, such as in warning signals'at railroad crossings,light houses, electric signs, and in other devices of similar character,and when the radiant energy emanates from a luminous source thisimproved switch is of great advantage as a control for electric operatedfuel burning equipment such as motor oper- 29 ated powdered fuelfurnaces, gas burning furnaces, industrial and domestic oil burners forheating systems, and the like.

This invention contemplates the forming of asealed switch tube,enclosing a gaseous fluid, with a movable'seal dividing the tube intotwo portions, having electrodes adapted to be connected and disconnectedby the movement of the seal, and imparting such movement to the seal byincreasing the temperature of the gaseous fluid in one end portion muchmore rapidly than that in the other end portion, whereby the gaseousfluid in that end will be caused to expand, overcome the pressure in theother end, and move the seal in that direction until the connectionbetween the electrodes is made or broken, as the case may be, and thencause the temperature of the greater expanded gaseous fluid to reducefaster than that in the other end of the tube. whereby the more rapidcontraction thereof will allow the pressure in the other end of the tubeto move the seal back to its original position.

While a prefered embodiment of this invention is illustrated upon theaccompanying sheets of drawings and is described in detail hereinafter,it is to be understood that this invention is no; limited to the exactconstruction shown. as it contemplates the broad idea of the employmentof an adiatherma- 1926. Serial No. 101,588.

nous medium co-acting with a source of radient energy to operate anelectric switch.

'In the drawing:

Fig. 1 is a view in longitudinal vertical section of a *prefered form ofmounting for this improved switch, illustrating the switch tube in endelevation.

Fig. 2 is an enlarged detail view in front elevation of the switchillustrated in Fig. 1.

Fig. 3 is a similar view illustrating the tube thereof in centralvertical section, and also illustrating a slight modification in thedetail construction of the tube.

\Vhile the tube employed in carrying out this invention may be formedfrom various materials as well as in various shapes, as contemplated bythe scope of this invention, for commercial reasons, it is preferablyformed of glass and for the purpose of compactness and assurance ofoperation, it is preferable to form the tube in the shape shown. Figs. 2and 3 illustrate a convenient commercial size.

Where it is desired to actuate this improved switch by radiant ener yfrom an actinic source, it may be prefera le to mount the switch tube inan uncovered position, however, where it is desired to actuate theswitch from a stationary luminous source of radiant energy, it may bepreferable to mount the switch tube in a casing having an openingexposing one side of the tube to the lummous source, inasmuch as radiantenergy travels in straightlines. Fig. 1 illustrates the latter typeadapted for application to a fuel burning device in which an electriccurrent is desired to be controlled by the existence of a flame from thefuel, and in which the ignition of the flame actuates the switch to makeor break the circuit, as desired, its failure after ignition actuatesthe switch to reverse the operation, and its failure to ignite will notaffect the switch.

The particular embodiment of this invention illustrated upon theaccompanying sheets of drawing comprises a sealed tube, preferably ofglass, having a reduced central portion 1 intermediate its ends, whichcentral portion is bent at an acute angle so that the enlarged endportions 2 appear to be somewhat of the shape of electric light bulbswith their adjacent circumferences in close proximity to each other, asshown in Figs. 2 and 3. The diameter of the reduced intermediate portionis sufficiently less than the diameters of the enlarged end portionswhen bent in the manner shown to allow a liquid seal to be formedtherein. A fluid conductor of electriclty 3, such as mercury, iscontained within the sealed tube of sufiicient quantity when the tube isin the position shown in Fig. 1, to enter into the branches of thereduced V-shaped portion 1 above the lowermost point of its upper wall,and thereby forming a liquid seal between the enlarged portion at eitherside thereof. Electrodes or terminals 4 of electric conducting materialare arranged to enter the interior of the tube and are sealed in thewalls thereof to be supported thereby, preferably in the manner shown inFigs. 1 and 2, which are of such dimensions that the electrode carriedby one enlarged portion extends into the reduced portion at that endsufficiently to be engaged, submerged or embraced by the fluidconducting material in the well formed by the angular bend in thisportion of the tube, while the electrode carried by the other enlargedportion will enter within the reduced portion of that end, terminatedshort of and out of contact with the upper surface of the fluidconducting material in the well. It is preferable to insert a gaseousfluid within the interior of the tube before it is completely sealed,which gaseous fluid is preferably of a nature to reduce arcing betweenthe electrodes and the fluid conducting material at the making orbreaking of an electric circuit therethrough. While the preferred mannerof supporting the electrodes and sealing them in the walls of the tubesis illnstrated, the particular manner in which electrodes are mounted isnot essential to this invention as long as they are mounted in such amanner as to prevent the escape of the enclosed gas. It is alsopreferable to provide an additional well 5 in the lower end of one ofthe enlarged end portions adjacent the reduced portion, as shown in Fig.2, into which the fluid conductor 3 may be caused to flow by tilting thetube in that direction or, from which the fluid conductor -may be causedto flow into the main body by tilting'the tube in the oppositedirection, whereby the amount of fluid conductor in the V-shaped well 1may be varied to meet various conditions.

It is recognized that radiant energy in the ether, generally known asthermal, luminous, or .actlnic energy, manifests itself according to thenature of the recipient upon which it falls and the rapidity with whichthe vibrations by which it is transmitted are executed. When the wavesor vibrations in the ether set up by radiant energy fall uponadiathermanous substances, the regular vibrations which constitutes thewaves are quenched and the energy of these vibrations passes into theenergy of the irregular motions to which heat is due, radiation isabsorbed and a rise of the temperature follows. Lamp black, or a surfacecovered with lamp black, is recognized as the most efficientadiathermanous medium which not only absorbs radiant energy from aluminous or actinic source, transforms its vibrations to produce heatand a rise in temperature, but also is a most eflicient medium for theemission of radiant energy. This property of adiathermanous substancesis employed to operate this switch by first, absorbing actinic orluminous energy to increase the temperature. by covering the entireouter or inner surface of one of the bulb-like end portions 2 with amedium adapted to secure a layer of lamp black to the walls, wherebywhen the tube is subjected to the rays or waves of light from the sun,electric. light, or from a flame I this lamp black surface being anadiathermanous substance absorbs theradiant energy therefrom andincreases the temperature of the walls surrounding that portion of thetube. The increasing of the temperature of the'walls of the tube alsoincreases the temperature of the gaseous fluid enclosed therein on thatside of the surface of the liquid fuel conductor 8 in the reducedportion 1 leading from that end, and,'as the temperature of the gaseousfluid in the lamp black covered end portion rises much more rapidly thanthe temperature of the gaseous fluid in the other enlarged end portion,the result is that the fluid conductor forming the seal in the wellbetween the two end portions is forced downward by the more rapidlyexpanding gas and moved upward in the opposite side of the well, withoutbreaking the seal between the two enlarged portions. and converesly whenthe switch is removed from the source of such radiant energy, theadiathermanous lamp black cover of the end portion will transmit or emitthe heat and reduce the temperature of the expanded gaseous fluidtherein much more rapidly, and thereby cause 1t to contract much morerapidly,

than the gaseous fluid in the other enlarged portion, whereby thepressure in the other enlarged portion will cause the fluid conductingseal to assume its original position.

The exterior portions of the respective electrodes 4 are each providedwith a flexible lead 5 adapted to be connected in the circuit to becontrolled by said switch. In Fig 0 the electrode in the enlarged endprovided with the adiathermanous covering is shown as normally extendingwithin the conducting fluid seal 3 with the electrode in the otherenlarged end normally terminated short and out 0 connection with saidfluid conductor,

so that when the flexible leads 5 are in circuit with the source ofelectricity, the circuit is normally broken through the switch as longas it is not subjected to radiant energy but as soon as it is laced incontact with the waves or rays of t e sun or from an electric light orflame, the gaseous fluid within the adiathermanous covered end willexpand with suflicient force to move the conducting fluid 3 in the well1 to contact and submerge the end of the electrode in the other enlargedend portion, while still maintaining electric contact with the firstelectrode, and thereby cause the circuit to be closed through theelectrodes and conducting fluid, and will maintain this electricalconnection as long as the switch is acted upon by such radiant energy.As soon as theswitch is removed from the source of electric energy, thegaseous fluid in the adiathermanous covered end will contract, allowingthe fluid seal to return to its original position and break the circuit.

Fig. 1 illustrates a preferred mounting for this switch when employed asa control in a fuel burning device, and, as shown, comprises acasing 6provided with clips 7 on the closed end thereof for engaging andsupporting the V-shaped restricted portion 1 and enlarged end portions 2of the tube, and with bindin posts 8 to which the free ends of the flexi1e leads 5 from the electrodes 4 are connected, which binding posts, inturn, provide means for connection with the circuit to be controlledthereby. Inasmuch as this switch is adapted to be operated by theluminous radiant energy emanating from the flame of the fuel within thefurnace, it is preferable to support the switch casing 6, at asuflicient distance therefrom so that the switch mechanism will not bedamaged by the intense heat from the furmade, by means of a tubularmember 9 secured to the open end of the casing and to a portion of thefurnace wall 10 surrounding an opening with the center line of suchtubular member in line with the flame from the fuel, and the innersurface of this tube may be polished or of reflecting material. whichwill reflect the rays or waves of luminous energy emanating from thatpart of the flame not in line with the center of the tube.

It will, therefore, be seen that this switch will readily control anelectric circuit as it will be actuated by the ignition of the flame ofthe fuel and to operate in one direction and upon failure of the fuelflame to operate in the opposite direction.

Fi 3 illustrates a slight modification in whic the restricted portion 1of the walls leading from the adiathermanous covered enlarged endportion is provided with an enlargement 11 in a horizontal directionterminating in a depending well 12 into which an electrode 13 may besupported by sealing the body thereof in the wall forming the bottom ofthe well. The exterior portion of such electrode is provided with aflexible connection 14 to a binding post 15 upon the back of the casing6 for connection with an electric circuit. As shown in Fig. 3, the fluidconductor 3 forms an electrical connection between the electrode 13 inthis additional well and the electrode 4 supported by the adiathermanouscovered enlar ed end portion, while the electrode in the ot er endportion is out of contact with the fluid conductor, so that uponexpansion of the as in adiathermanous end portion, the liqui conductorwill be caused to flow upward away from the electrode 13 in theadditional well 12 into the other arm of the V-shaped restricted portion1, breaking the electrical connection first mentioned and making anelectrical connection between the electrodes 4' in the two enlarged endportions 2 and upon the contraction of the gaseous fluid in theadiathermanous covered end portion the operation will be reversed.

As above stated, various substances or materials may be employed in theformation of the sealed tubes and the operation above described will becarried on in the same way, but at a rate varying with the materialemployed. For the commercial device, it is preferable to construct thetube of glass, both for the convenience in sealing the electrodestherein and for the reason that glass is a diathermanous substance whichreadily transmits the waves of radiant energy with but littleabsorption. The additional well 5, formed as shown in Fig. 1, may becalled an adjusting well as it is employed to adjust the level of theliquid fluid conductor 3 in the V-shaped arms of the reduced portion 1to approach or recede from the electrodes in the end portions foradjusting the length of time consumed after subjecting theadiathermanous covered end portion to a source of radiant energy tocause the electrical connection to be made or broken through the switch.

As above set forth, it is preferable that one of the enlarged endportions of this switch be of, or covered with, an adiathermanoussubstance and the other enlarged end portion, in accordance with thisinvent-ion, may be of, or covered with, any substance, eitherdiathermanous or adiathermanous, as long as it absorbs less radiantenergy, that is, as long as it transforms the waves of radiant enerimpinging upon it to produce a lesser egree of heat than that of thefirst mentioned portion, as for instance, one end portion may be coveredwith a layer of lamp black, the most efiicient adiathermanous medium,and the other end portion be silvered, or rovided with a covering ofreflecting materia whereby the waves of radiant energy impinging upon itwill be reflected.

Likewise the tube may be of any shape as long as it is divided into endportions by a movable seal so that the gaseous fluid in one end portionmay be caused by radiant energy to expand more rapidly than the gaseousfluid in the other end portion, even where both end portions are equallysubjected to the waves of radiant energy emanating from the same source.

If the surface of one enlar ed end portion is covered with a substance tat absorbs radiant energy and increases the temperature of the enclosedgaseous fluid so much more rapidl and to such a higher degree that itexpands t e gaseous fluid to such an extent as would cause a solidmovable seal to leave the contracted portion or well, by the employmentof a liquid seal, such a rapid expansion is accommodated by allowing thehigh pressure gas to pass through the liquid from one end to the otherin small quantities in the form of bubbles, so that an excessivemovement of the liquid seal is prevented, which in the con structiondescribed prevents a failure of the establishment of the electricalconnection by the electric conducting, fluid, and serves to cause arapid return of the conducting fluid to its original position upon theremoval of the source of radiant energy.

What I claim is:

A sealed tube containing a gaseous fluid and having a plurality ofintermediate depressed portions forming a plurality of separated wells,a fluid conductor of electricity 5 in said tube adapted to be caused toflow from one well to another and form a liquid seal between the endportions, a plurality of electric terminals entering the interior of thetube adapted to be engaged by the fluid conductor to complete anelectric connection therebetween, one of the end portions of the tubehaving means, when the tube is subjected to radiant energy to absorbheat therefrom, expand the gaseous fluid in that end of the tube todepress the level of the fluid conductor in that end of the well to makeor break the electric connection between a pair of said terminals, theamount of liquid in the'sealing well adapted to be increased ordiminished by causing a flow from or to another well to control'thedegree of expansion of the gaseous fluid required to move the fluid inthe sealing well to make or break theclectric connection between saidterminals.

IRA E. MOCABE.

